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The ALMaQUEST survey IX: The nature of the resolved star forming main sequence

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Maiolino, R 
Bluck, AFL 
Lin, L 


We investigate the nature of the scaling relations between the surface density of star formation rate (ΣSFR), stellar mass (Σ), and molecular gas mass (ΣH2), aiming at distinguishing between the relations that are primary, i.e. more fundamental, and those which are instead an indirect by-product of the other relations. We use the ALMaQUEST survey and analyse the data by using both partial correlations and Random Forest regression techniques. We unambiguously find that the strongest intrinsic correlation is between ΣSFR and ΣH2 (i.e. the resolved Schmidt-Kennicutt relation), followed by the correlation between ΣH2 and Σ (resolved Molecular Gas Main Sequence, rMGMS). Once these two correlations are taken into account, we find that there is no evidence for any intrinsic correlation between ΣSFR and Σ, implying that SFR is entirely driven by the amount of molecular gas, while its dependence on stellar mass (i.e. the resolved Star Forming Main Sequence, rSFMS) simply emerges as a consequence of the relationship between molecular gas and stellar mass.



galaxies: evolution, galaxies: formation, galaxies: fundamental parameters, galaxies: star formation

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Monthly Notices of the Royal Astronomical Society

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Oxford University Press (OUP)
European Research Council (695671)
STFC (2440936)
Science and Technology Facilities Council (STFC). ERC Advanced Grant 695671 "QUENCH".